The disclosure concerns a pressure change damper for a hydraulic vehicle brake system with brake force control, and a hydraulic vehicle brake system with brake force control with such a pressure change damper.
Brake force control means that wheel brake pressures in the wheel brakes and hence the brake forces of the wheel brakes of a hydraulic vehicle brake system can be controlled preferably per individual wheel, for example for anti-lock braking, traction control, and/or electronic stability control which is generally also known as slide-slip control, or an automatic braking system or automatic cruise control, for which abbreviations such as ABS, ASR, FDR, ESP, ACC are commonly used. The list is exemplary and not conclusive. Such brake force controllers are known in principle and will not therefore be described in more detail.
Hydraulic vehicle brake systems with brake force control normally have a hydraulic pump, usually one hydraulic pump per brake circuit, also known as a return pump, which is often a piston pump. Because of their oscillating pumping manner, piston pumps cause pressure fluctuations in a brake fluid of a hydraulic vehicle brake system. Solenoid valves for wheel brake pressure regulation, when switching, cause pressure pulses in the brake fluid. To damp such pressure changes in the brake fluid of a hydraulic vehicle brake system, pressure change dampers are known which also reduce a noise generation and a repercussion on the brake master cylinder.
International patent application WO 2011/028 376 A2 discloses a hydraulic vehicle brake system with brake force control, with a tandem or dual circuit brake master cylinder to which two brake circuits are connected. To control the brake force, the known vehicle brake system has solenoid valves, check valves and in each brake circuit a high-pressure accumulator, a piston pump and a pressure change damper which is connected to a pump outlet of the piston pump, i.e. to a pressure side of the piston pump. In one embodiment, the known pressure change damper has a dome-like, rigid damper housing in which a hose-like damper element made of elastomer is arranged. Dome-like here means a tubular form closed at one end and open at the opposite end. The damper element also has a closed end which is arranged in the closed end of the damper housing. An open end of the damper element is arranged on or in the open end of the damper housing. The pressure change damper is arranged in a receiver bore in a hydraulic block of a brake force controller of a hydraulic vehicle brake system, wherein the closed ends of the damper housing and the damper element face a base of the receiver bore. A plug-like holder is pressed into an opening of the receiver bore in the hydraulic block, to seal the receiver bore in a pressure- and fluid-tight fashion, and establishes an outwardly protruding edge at the open end of the damper element between a flange at the open end of the damper housing and a ring step of the holder. The plug-like holder is fixed in the opening of the receiver bore in a so-called self-clinch fixing. Self-clinch means a circumferential caulking system in which, on pressing in the holder, the material of the hydraulic block deforms plastically into a circumferential groove of the holder, to form a pressure- and fluid-tight seal between the receiver bore and the holder. For deforming, the holder has a ring shoulder with a greater diameter than the rest of the holder which lies behind the circumferential groove in the pressing direction.